Photo Gallery: Chalk Chrusher
The pictures are of a very large quarrying
machine for crushing chalk to a useable size and depositing it onto
a conveyor for transportation to the cement factory.
Two of these machines were installed in
two chalk quarries serving the same cement factory, one in a quarry
digging high chalk and one in a quarry digging low chalk. To manufacture
the correct quality cement, differing amounts of each chalk must be
mixed, as the chrushers were loaded by large earthmoving machines is
could not be achieved easily manually.
The crushers were driven by very large
closed loop hydraulic systems (450L/min @ 200Bar) driving B400 Staffa
motors, these motors ran the conveyors that drove the chalk under the
rotating crusher drums. The amount of chalk delivered could be varied
by adjusting the speed of the motors by automatic radio signal from
the factory over 2km away.
Both the hydraulic system and the crusher
drum were driven by 200kw electric motors powered from the local National
Grid pylons at 3,300 volts.
The hydraulic system also drove the tracks
that the machine sits on at a max speed of 0.5kph which is fast enough
when the machine is in normal use. However if the machine needs to be
moved long distances a diesel driven power pack would be placed into
the chalk hopper and two men can drive the machine by walking between
the tracks, this is a very slow process, I know because I have driven
the machine for 6 hours in very bad weather conditions.
Click image for close-up